1. Field of the Invention
The invention relates generally to the usability of the computer-human interface and, more specifically, to defining and utilizing a method that provides an objective, quantitative measurement of the mental effort expended during manipulation of a computer-human interface.
2. Prior Art
Software systems designed for a general purpose computer provide a component to accomplish the functionality specified for the system and a component to expedite both the declaration of data to the computer and the specification of transformations to these data. Software of this latter component plus the input-output devices employed during communication with the computer will comprise the computer-human interface (CHI). Great effort has been expended by cognitive psychologists and software engineers to investigate cognitive factors involved in designing productive CHI that are easily learned, easily retained, and not prone to error. It is apparent that if an objective, quantitative technique were available for measuring the mental effort while manipulating a computer it would advance our ability to design CHI of high usability. Such a tool would find ready application in the areas of: (1) designing interfaces for new application software, (2) comparing the usability of extant software of equivalent functionality, and (3) the screening of applicants for computer based employment and evaluation of employees engaged in computer based employment.
The review of the current state of the cognitive arts relating to computer-human interface design presented below shows that these arts have not articulated an objective, quantitative technique for measuring the mental effort expended by a user while manipulating a CHI. It will then be shown how the present invention overcomes this failure.